The present invention refers to a construction of a refrigeration circuit for refrigeration systems having a hermetic compressor and a condenser, of the type used in small refrigeration appliances of domestic use, such as refrigerators and freezers.
In the conventional refrigeration systems, the refrigeration circuit comprises, essentially and sequentially, a hermetic compressor, a condenser, a pressure reducing element, such as a capillary tube, an evaporator and a return line.
In this circuit, the hermetic compressor draws the low pressure refrigerant gas and pumps it to the condenser as a high pressure hot gas. Upon passing through the condenser, said gas is liquefied, losing heat to the environment.
From the condenser, the refrigerant liquid is led to the evaporator, after having its pressure reduced in the capillary tube, where it reaches its gaseous state again, before being drawn by the compressor, starting a new cycle.
In domestic or commercial refrigeration systems, there are used air cooled condensers, which are designed to dissipate the heat transferred to the refrigerant fluid in the evaporator and during compression in the compressor, as well as to condense this refrigerant fluid, making it become liquid.
In small refrigeration systems, the condenser used may have forced or natural ventilation (static refrigeration). In these systems, in which said condenser has a very small volume, at the start of the compressor after a long stop period, all gas load is pumped to the condenser, making the condensation pressure increase and, in many cases, exceed acceptable values. This occurs because, most of the time, the volume of the condensers does not take up the volume of the gas load or, when it does so, the heat exchange area is diminished. During start, the refrigerant fluid contained in the condenser is in the liquid form.
In these situations, there occurs an accumulation of liquid in the condenser, from an outlet portion thereof, which tends to fill up its whole volume, gradually reducing the effective condensation area of the condenser. The condensation pressure may increase to such values as to impair the bearings and/or valves of the compressor and also make the compressor stop working.
In order to reduce damages, these systems require, either a larger condenser, which is usually infeasible due to the dimensions of the product to which it is applied, or the use of very strong motors, increasing the cost of the system, considering that these situations occur few times, for example when the equipment is turned off for cleaning or transportation.
Thus, it is an object of the present invention to provide an improvement in a refrigeration circuit for a refrigeration system which, with reduced cost and easy construction, may minimize the presence of liquids in the condenser, soon after the start of the compressor which has had a long stop period, maintaining constant the useful condensation area of the condenser, without requiring stronger motors.
These and other objectives are achieved by an improvement in a refrigeration circuit, including: a hermetic compressor having a shell; and a condenser having an inlet connected to a discharge outlet of the compressor and an outlet, and comprising a hermetic chamber maintained in fluid communication with the refrigeration circuit, immediately downstream at least one of the parts defined by the condenser and by the compressor, and which is dimensioned to store, in conditions of long stops of the compressor and of a start thereof, a substantial volume of refrigerant fluid, said hermetic chamber returning to the refrigeration circuit substantially all the refrigerant fluid stored therein, after said conditions have ended.